<!DOCTYPE html>
<html lang="en">
 <head>
  <meta charset="UTF-8">
  
 </head>
 <body>
  <script>
var str = '1a2b3c4d5e';
console.log(str.match('h'));	//返回null
console.log(str.match('b'));	//返回["b", index: 3, input: "1a2b3c4d5e"]
console.log(str.match(/b/));	//返回["b", index: 3, input: "1a2b3c4d5e"]

  </script>
 </body>
</html>
